Thought I would update those who were following my situation. 6 days in the shop before a BMW expert was flown in (also to look at two 7 series). He had them replace Oxygen Sensor and the tank venting valve. They still do not know if it is fixed. They spent 3 more days with it. I am now driving it and waiting for the tank to run low to give it a try by puting a full tank of gas in and seeing if it stalls or misfires again. Hope not, but they have given me zero confidence so far. . I will let you know if that was the ticket.